Fumaric acid or trans-butenedioic acid is the chemical compound with the formula HO2CCH=CHCO2H. It is produced in eukaryotic organisms from succinate in complex 2 of the electron transport chain via the enzyme succinate dehydrogenase. It is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid. In fumaric acid the carboxylic acid groups are trans (E) and in maleic acid they are cis (Z). Fumaric acid has a fruit-like taste.

The salts and esters are known as fumarates. Fumarate can also refer to the C4H2O4−− ion (in solution).

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Fumaric acid was first prepared from succinic acid.[3] A traditional synthesis involves oxidation of furfural (from the processing of maize) using chlorate in the presence of a vanadium-based catalyst.[4] Currently, industrial synthesis of fumaric acid is mostly based on catalyticisomerisation of maleic acid in aqueous solutions at low pH. Maleic acid is accessible in large volumes as a hydrolysis product of maleic anhydride, produced by catalytic oxidation of benzene or butane.[5]

Fumaric acid does not combust in a bomb calorimeter under conditions where maleic acid deflagrates smoothly. For teaching experiments designed to measure the difference in energy between the cis- and trans- isomers, a measured quantity of carbon can be ground with the subject compound and the enthalpy of combustion computed by difference.

Fumaric acid has been used as a food acidulant since 1946. It is approved for use as a food additive in the EU,[7] USA[8] and Australia and New Zealand.[9] As a food additive, it is used as an acidity regulator and can be denoted by the E number E297. It is generally used in beverages and baking powders for which requirements are placed on purity. It is generally used as a substitute for tartaric acid and occasionally in place of citric acid, at a rate of 1 g of fumaric acid to every ~1.5 g of citric acid, in order to add sourness, similarly to the way malic acid is used. As well as being a component of some artificial vinegar flavors, such as "Salt and Vinegar" flavored potato chips,[10] it is also used as a coagulant in stovetop pudding mixes.

Various Fumaric acid esters (FAES) have specific immunomodulating (respectively moderate immunosuppression) properties which are responsible for certain effects in the treatment of psoriasis. In the Netherlands, Germany, Austria and the Benelux countries substances derived from fumaric acid have been used for half a century for this purpose.[12] Although it seems that a certain effectiveness exists (and many studies have confirmed the effect), more statistically powerful studies are necessary to provide better evidence of the effectiveness of fumaric acid esters in treatment of psoriasis (e.g. more accurate in terms of the dermatological nosology of this autoimmune disease). Such studies should in the future help specify which psoriasis variants (in terms of the course, the immunological profile of the patient etc.) are suited to be treated with fumaric acid esters.

Fumaric acid is naturally present in the herb called Fumaria officinalis. The top of this herb is used to treat various skin disorders including psoriasis. Baths with this herb have been used for several centuries.[13] At present, these baths (after consultation with a general practitioner or dermatologist) are used as an adjunct therapy to basic treatment.

Fumaric acid is used in the manufacture of polyesterresins and polyhydric alcohols and as a mordant for dyes. Since the early 21st century, it has been used to synthesize one of the first metal-organic frameworks presenting commercial applications thanks to its remarkable adsorption and mechanical properties, combined with a low toxicity compared to other well-studied MOFs.[14]

1.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses

2.
DrugBank
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The DrugBank database is a comprehensive, freely accessible, online database containing information on drugs and drug targets. As both a bioinformatics and a resource, DrugBank combines detailed drug data with comprehensive drug target information. Because of its scope, comprehensive referencing and unusually detailed data descriptions. As a result, links to DrugBank are maintained for nearly all drugs listed in Wikipedia, DrugBank is widely used by the drug industry, medicinal chemists, pharmacists, physicians, students and the general public. Its extensive drug and drug-target data has enabled the discovery and repurposing of a number of existing drugs to treat rare, the latest release of the database contains 8227 drug entries including 2003 FDA-approved small molecule drugs,221 FDA-approved biotech drugs,93 nutraceuticals and over 6000 experimental drugs. Additionally,4270 non-redundant protein sequences are linked to these drug entries, each DrugCard entry contains more than 200 data fields with half of the information being devoted to drug/chemical data and the other half devoted to drug target or protein data. Four additional databases, HMDB, T3DB, SMPDB and FooDB are also part of a suite of metabolomic/cheminformatic databases. The first version of DrugBank was released in 2006 and this early release contained relatively modest information about 841 FDA-approved small molecule drugs and 113 biotech drugs. It also included information on 2133 drug targets, the second version of DrugBank was released in 2009. This greatly expanded and improved version of the database included 1344 approved small molecule drugs and 123 biotech drugs as well as 3037 unique drug targets. Version 2.0 also included, for the first time, withdrawn drugs and illicit drugs, version 3.0 was released in 2011. This version contained 1424 approved small molecule drugs and 132 biotech drugs as well as >4000 unique drug targets, version 3.0 also included drug transporter data, drug pathway data, drug pricing, patent and manufacturing data as well as data on >5000 experimental drugs. Version 4.0 was released in 2014 and this version included 1558 FDA-approved small molecule drugs,155 biotech drugs and 4200 unique drug targets. Version 4.0 also incorporated information on drug metabolites, drug taxonomy, drug spectra, drug binding constants. Table 1 provides a complete statistical summary of the history of DrugBank’s development. All data in DrugBank is non-proprietary or is derived from a non-proprietary source and it is freely accessible and available to anyone. In addition, nearly every item is fully traceable and explicitly referenced to the original source. DrugBank data is available through a web interface and downloads

3.
E number
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E numbers are codes for substances that are permitted to be used as food additives for use within the European Union and Switzerland. Commonly found on labels, their safety assessment and approval are the responsibility of the European Food Safety Authority. Having a single unified list for food additives was first agreed upon in 1962 with food colouring, in 1964, the directives for preservatives were added,1970 for antioxidants and 1974 for the emulsifiers, stabilisers, thickeners and gelling agents. They are increasingly, though rarely, found on North American packaging. In some European countries, E number is used informally as a pejorative term for artificial food additives. This is incorrect, because many components of foods have E numbers, e. g. vitamin C. NB, Not all examples of a fall into the given numeric range. Moreover, many chemicals, particularly in the E400–499 range, have a variety of purposes, the list shows all components that have or had an E-number assigned. Not all additives listed are still allowed in the EU, but are listed as they used to have an E-number, for an overview of currently allowed additives see here. Includes Lists of authorised food additives Food additives database

4.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure

5.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES

6.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH

7.
Density
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The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume, ρ = m V, where ρ is the density, m is the mass, and V is the volume. In some cases, density is defined as its weight per unit volume. For a pure substance the density has the numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity, osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. Thus a relative density less than one means that the floats in water. The density of a material varies with temperature and pressure and this variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object, increasing the temperature of a substance decreases its density by increasing its volume. In most materials, heating the bottom of a results in convection of the heat from the bottom to the top. This causes it to rise relative to more dense unheated material, the reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is a property in that increasing the amount of a substance does not increase its density. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass, upon this discovery, he leapt from his bath and ran naked through the streets shouting, Eureka. As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment, the story first appeared in written form in Vitruvius books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time, from the equation for density, mass density has units of mass divided by volume. As there are units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per metre and the cgs unit of gram per cubic centimetre are probably the most commonly used units for density.1,000 kg/m3 equals 1 g/cm3. In industry, other larger or smaller units of mass and or volume are often more practical, see below for a list of some of the most common units of density

8.
Melting point
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The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid to solid. Because of the ability of some substances to supercool, the point is not considered as a characteristic property of a substance. For most substances, melting and freezing points are approximately equal, for example, the melting point and freezing point of mercury is 234.32 kelvins. However, certain substances possess differing solid-liquid transition temperatures, for example, agar melts at 85 °C and solidifies from 31 °C to 40 °C, such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is close to 0 °C. In the presence of nucleating substances the freezing point of water is the same as the melting point, the chemical element with the highest melting point is tungsten, at 3687 K, this property makes tungsten excellent for use as filaments in light bulbs. Many laboratory techniques exist for the determination of melting points, a Kofler bench is a metal strip with a temperature gradient. Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point, differential scanning calorimetry gives information on melting point together with its enthalpy of fusion. A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window, the several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated and with the aid of the melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, the measurement can also be made continuously with an operating process. For instance, oil refineries measure the point of diesel fuel online, meaning that the sample is taken from the process. This allows for more frequent measurements as the sample does not have to be manually collected, for refractory materials the extremely high melting point may be determined by heating the material in a black body furnace and measuring the black-body temperature with an optical pyrometer. For the highest melting materials, this may require extrapolation by several hundred degrees, the spectral radiance from an incandescent body is known to be a function of its temperature. An optical pyrometer matches the radiance of a body under study to the radiance of a source that has been previously calibrated as a function of temperature, in this way, the measurement of the absolute magnitude of the intensity of radiation is unnecessary. However, known temperatures must be used to determine the calibration of the pyrometer, for temperatures above the calibration range of the source, an extrapolation technique must be employed

9.
Aqueous solution
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An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant chemical formula, for example, a solution of table salt, or sodium chloride, in water would be represented as Na+ + Cl−. The word aqueous means pertaining to, related to, similar to, as water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Substances that are hydrophobic often do not dissolve well in water, an example of a hydrophilic substance is sodium chloride. Acids and bases are aqueous solutions, as part of their Arrhenius definitions, the ability of a substance to dissolve in water is determined by whether the substance can match or exceed the strong attractive forces that water molecules generate between themselves. If the substance lacks the ability to dissolve in water the molecules form a precipitate, reactions in aqueous solutions are usually metathesis reactions. Metathesis reactions are another term for double-displacement, that is, when a cation displaces to form a bond with the other anion. The cation bonded with the latter anion will dissociate and bond with the other anion, aqueous solutions that conduct electric current efficiently contain strong electrolytes, while ones that conduct poorly are considered to have weak electrolytes. Those strong electrolytes are substances that are ionized in water. Nonelectrolytes are substances that dissolve in water yet maintain their molecular integrity, examples include sugar, urea, glycerol, and methylsulfonylmethane. When writing the equations of reactions, it is essential to determine the precipitate. To determine the precipitate, one must consult a chart of solubility, soluble compounds are aqueous, while insoluble compounds are the precipitate. Remember that there may not always be a precipitate, when performing calculations regarding the reacting of one or more aqueous solutions, in general one must know the concentration, or molarity, of the aqueous solutions. Solution concentration is given in terms of the form of the prior to it dissolving. Metal ions in aqueous solution Solubility Dissociation Acid-base reaction theories Properties of water Zumdahl S.1997, 4th ed. Boston, Houghton Mifflin Company

10.
Acid dissociation constant
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An acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the constant for a chemical reaction known as dissociation in the context of acid–base reactions. In the example shown in the figure, HA represents acetic acid, and A− represents the acetate ion, the chemical species HA, A− and H3O+ are said to be in equilibrium when their concentrations do not change with the passing of time. The definition can then be more simply H A ⇌ A − + H +, K a = This is the definition in common usage. A weak acid has a pKa value in the approximate range −2 to 12 in water, pKa values for strong acids can, however, be estimated by theoretical means. The definition can be extended to non-aqueous solvents, such as acetonitrile and dimethylsulfoxide. Denoting a solvent molecule by S H A + S ⇌ A − + S H +, K a = When the concentration of solvent molecules can be taken to be constant, K a =, as before. The value of pKa also depends on structure of the acid in many ways. For example, Pauling proposed two rules, one for successive pKa of polyprotic acids, and one to estimate the pKa of oxyacids based on the number of =O and −OH groups. Other structural factors that influence the magnitude of the dissociation constant include inductive effects, mesomeric effects. Hammett type equations have frequently applied to the estimation of pKa. The quantitative behaviour of acids and bases in solution can be only if their pKa values are known. These calculations find application in different areas of chemistry, biology, medicine. Acid dissociation constants are essential in aquatic chemistry and chemical oceanography. In living organisms, acid–base homeostasis and enzyme kinetics are dependent on the pKa values of the acids and bases present in the cell. According to Arrheniuss original definition, an acid is a substance that dissociates in solution, releasing the hydrogen ion H+. The equilibrium constant for this reaction is known as a dissociation constant. Brønsted and Lowry generalised this further to an exchange reaction

11.
Carboxylic acid
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A carboxylic acid /ˌkɑːrbɒkˈsɪlɪk/ is an organic compound that contains a carboxyl group. The general formula of an acid is R–COOH, with R referring to the rest of the molecule. Carboxylic acids occur widely and include the amino acids and acetic acid, salts and esters of carboxylic acids are called carboxylates. When a carboxyl group is deprotonated, its conjugate base forms a carboxylate anion, carboxylate ions are resonance-stabilized, and this increased stability makes carboxylic acids more acidic than alcohols. Carboxylic acids can be seen as reduced or alkylated forms of the Lewis acid carbon dioxide, carboxylic acids are commonly identified using their trivial names, and usually have the suffix -ic acid. IUPAC-recommended names also exist, in system, carboxylic acids have an -oic acid suffix. For example, butyric acid is butanoic acid by IUPAC guidelines, the -oic acid nomenclature detail is based on the name of the previously-known chemical benzoic acid. Alternately, it can be named as a carboxy or carboxylic acid substituent on another parent structure, for example, 2-carboxyfuran. The carboxylate anion of an acid is usually named with the suffix -ate, in keeping with the general pattern of -ic acid and -ate for a conjugate acid and its conjugate base. For example, the base of acetic acid is acetate. The radical •COOH has only a fleeting existence. The acid dissociation constant of •COOH has been measured using electron paramagnetic resonance spectroscopy, the carboxyl group tends to dimerise to form oxalic acid. Because they are both hydrogen-bond acceptors and hydrogen-bond donors, they participate in hydrogen bonding. Together the hydroxyl and carbonyl group forms the functional group carboxyl, carboxylic acids usually exist as dimeric pairs in nonpolar media due to their tendency to self-associate. Smaller carboxylic acids are soluble in water, whereas higher carboxylic acids are less due to the increasing hydrophobic nature of the alkyl chain. These longer chain acids tend to be soluble in less-polar solvents such as ethers. Carboxylic acids tend to have higher boiling points than water, not only because of their surface area. Carboxylic acids tend to evaporate or boil as these dimers, for boiling to occur, either the dimer bonds must be broken or the entire dimer arrangement must be vaporised, both of which increase the enthalpy of vaporization requirements significantly

12.
Maleic acid
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Maleic acid or cis-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Maleic acid is the cis-isomer of butenedioic acid, whereas fumaric acid is the trans-isomer and it is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications. Maleic acid is a stable molecule than fumaric acid. The difference in heat of combustion is 22.7 kJ·mol−1, the heat of combustion is -1355 kJ/mole. Maleic acid is soluble in water than fumaric acid. The melting point of maleic acid is much lower than that of fumaric acid. In industry, maleic acid is derived by hydrolysis of maleic anhydride, maleic acid is an industrial raw material for the production of glyoxylic acid by ozonolysis. Maleic acid may be used to form acid salts with drugs to make them more stable. Maleic acid is used as an adhesion promoter for different substrates, such as nylon and zinc coated metals e. g galvanized steel. The major industrial use of acid is its conversion to fumaric acid. This conversion, an isomerization, is catalysed by a variety of reagents, such as mineral acids, again, the large difference in water solubility makes fumaric acid purification easy. The isomerization is a topic in schools. Maleic acid and fumaric acid do not spontaneously interconvert because rotation around a carbon double bond is not energetically favourable. However, conversion of the cis isomer into the trans isomer is possible by photolysis in the presence of an amount of bromine. Light converts elemental bromine into a radical, which attacks the alkene in a radical addition reaction to a bromo-alkane radical. The bromine radicals recombine and fumaric acid is formed, in another method, maleic acid is transformed into fumaric acid through the process of heating the maleic acid in hydrochloric acid solution. Reversible addition leads to free rotation about the central C-C bond and formation of the more stable, some bacteria produce the enzyme maleate isomerase, which is used by bacteria in nicotinate metabolism. This enzyme catalyses isomerization between fumarate and maleate, although not practised commercially, maleic acid can be converted into maleic anhydride by dehydration, to malic acid by hydration, and to succinic acid by hydrogenation

13.
Succinic acid
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Succinic acid is a dicarboxylic acid with the chemical formula 22. The name derives from Latin succinum, meaning amber, succinate is generated in mitochondria via the tricarboxylic acid cycle, an ancient energy-yielding process shared by all organisms. As such, succinate links cellular metabolism to the regulation of cellular function, dysregulation of succinate synthesis and degradation can lead to pathological conditions, such as malignant transformation, inflammation and tissue injury. Succinic acid is a white, odorless solid with an acidic taste. In an aqueous solution, succinic acid readily ionizes to form its conjugate base, succinate. As a diprotic acid, succinic acid undergoes two successive reactions,22 → 2− + H+ 2− → 222− + H+ The pKa of these processes are 4.3 and 5.6. Both anions are colorless and can be isolated as the salts, e. g. Na2, in living organisms, primarily succinate, not succinic acid, is found. As a radical group it is called a succinyl group, like most simple mono- and dicarboxylic acids, it is not harmful but can be an irritant to skin and eyes. Succinic acid can be oxidized to fumaric acid or be converted to diesters and this diethyl ester is a substrate in the Stobbe condensation. Dehydration of succinic acid gives succinic anhydride, succinate can be used to derive 1, 4-butanediol, maleic anhydride, succinimide, 2-pyrrolidinone and tetrahydrofuran. Historically, succinic acid was obtained from amber by distillation and has thus been known as spirit of amber, today, succinic acid is generated for human use synthetically or converted from biomass via fermentation. Common industrial routes of synthesis include partial hydrogenation of maleic acid, oxidation of 1, 4-butanediol, succinate is also produced petrochemically from butane via maleic anhydride. Additionally, genetic engineering of bacteria, such as Escherichia coli or Saccharomyces cerevisiae, has allowed for the high-yielding. Global production is estimated at 16,000 to 30,000 tons a year, in 2004, succinate was placed on the US Department of Energys list of top 12 platform chemicals from biomass. Succinic acid is a precursor to polyesters and a component of some alkyd resins. A key derivative of succinic acid,1, 4-butanediol, has industrial applications. The global market size for BDO was estimated at USD4.72 billion in 2013, BDO is a precursor to the common organic solvent THF and a precursor to polybutylene terephthalate, an engineering-grade thermoplastic. The automotive and electronics industries heavily rely on PBT to produce connectors, insulators, wheel covers, gearshift knobs, Succinic acid also serves as the bases of certain biodegradable polymers, which are of interest in tissue engineering applications

14.
Crotonic acid
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Crotonic acid or is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. It is also called crotonic acid because it was thought to be a saponification product of croton oil. It crystallizes as needles from hot water, the cis-isomer of crotonic acid is called isocrotonic acid. 0°. The unit cell contains four formula units, the compound is soluble in water and many organic solvents such as ethanol, acetone or toluene. Its odor is similar to acid and irritates eyes, skin. Crotonic acid can be converted into butanoic acid by hydrogenation with zinc and it forms with elemental chlorine or bromine 2, 3-dihalogenbutanoic acids, The electrophilic addition of hydrogen bromide forms 3-bromobutanoic acid. The substitution pattern arises from the effect of the carboxyl group. The carbenium ion is more stable at position 3, this is where the bromine anion attaches, the reaction with alkaline potassium permanganate solution affords 2, 3-dihydroxybutanoic acid. Crotonic acid is used for the preparation of DL-threonine by alpha-functionalization using mercury acetate, for the production of plastics, it may be copolymerized with vinyl acetate. Crotonyl chloride reacts with N-ethyl-2-methylaniline to provide crotamiton, which is used as an agent against scabies, Crotyl Crotyl alcohol Isocrotonic acid Methacrylic acid

15.
Dimethyl fumarate
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Dimethyl fumarate is the methyl ester of fumaric acid. DMF was initially recognized as a very effective hypoxic cell radiosensitizer, later, DMF combined with three other fumaric acid esters was licensed in Germany as oral therapy for psoriasis. Other diseases, such as necrobiosis lipoidica, granuloma annulare, phase III clinical trials found that DMF successfully reduced relapse rate and increased time to progression of disability in multiple sclerosis. DMF is thought to have immunomodulatory properties without significant immunosuppression, in a non-medical use, DMF was applied as a biocide in furniture or shoes to prevent growths of mold during storage or transport in a humid climate. Dimethyl fumarate was shown to have a significant effect on relapse rate, Dimethyl fumarate was recommended for approval in the European Union as a peroral treatment for MS by EMA on March 21,2013. One serious side effect that has been described is progressive multifocal leukoencephalopathy, Dimethyl fumarate is an ester and an α, β-unsaturated electrophilic compound which can quickly undergo Michael additions with nucleophiles. Dimethyl fumarate is also an effective diene acceptor in the thermal Diels-Alder reaction, due to the geometry of the starting ester, the Diels-Alder product will have a trans configuration. With this reaction, compounds with bicyclo skeletons can be synthesized, e. g. a diester with a skeleton from dimethyl fumarate. The precise mechanism of action of dimethyl fumarate is unknown, the compound activates the nuclear factor -like 2 pathway and has been identified as a nicotinic acid receptor agonist in vitro. Dimethyl fumarate is a lipophilic, highly mobile molecule in human tissue, as a α, β-unsaturated electrophilic compound, dimethyl fumarate is rapidly attacked by the detoxifying agent glutathione in a Michael addition reaction. Dimethyl fumarate is highly reactive, when administered orally, it does not survive long enough to be absorbed into blood without being attacked by GSH, however, part of it is hydrolyzed by esterases to produce monomethylfumarate, which is more resistant. Dimethyl fumarate has been found to be an allergic sensitizer at very low concentrations, concentrations as low as 1 ppm may produce allergic reactions. There are only a handful of equally potent sensitizers, in Finland where the chairs were sold from 2006–2007, sixty users were given serious rashes. In the United Kingdom, sofas sold by Argos, Land of Leather, complaints have been made that dates on the sofas were altered and sofas containing the sachets sold. Land of Leather and Walmsley are facing a ₤10 million class action suit over their reaction to the incident, the danger came to public attention when the BBC Watchdog program alerted consumers to the sofas. In the European Union the use of dimethyl fumarate for consumer products has been forbidden since 1998, the ban on dimethyl fumarate as laid down in Decision 2009/251 establishes a maximum concentration of dimethyl fumarate in products of 0.1 ppm. Products containing more than 0.1 ppm dimethyl fumarate shall be withdrawn from the market, fishersci. ca, Dimethyl fumarate Material Safety Data Sheet

16.
Iron(II) fumarate
–
Iron fumarate, also known as ferrous fumarate, is the iron salt of fumaric acid, occurring as a reddish-orange powder, used to supplement iron intake. It has the chemical formula C4H2FeO4, pure ferrous fumarate has an iron content of 32. 87%, therefore one tablet of 300 mg iron fumarate will contain 98.6 mg of iron. Ferrous fumurate is often taken by mouth as an iron supplement

17.
Chemical compound
–
A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can be converted to a different chemical composition by interaction with a chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AC + BD, where A, B, C, and D are each unique atoms, and AB, CD, AC, and BD are each unique compounds. A chemical element bonded to a chemical element is not a chemical compound since only one element. Examples are the diatomic hydrogen and the polyatomic molecule sulfur. Chemical compounds have a unique and defined chemical structure held together in a spatial arrangement by chemical bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms. There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Characteristic properties of compounds include that elements in a compound are present in a definite proportion, for example, the molecule of the compound water is composed of hydrogen and oxygen in a ratio of 2,1. In addition, compounds have a set of properties. The physical and chemical properties of compounds differ from those of their constituent elements, however, mixtures can be created by mechanical means alone, but a compound can be created only by a chemical reaction. Some mixtures are so combined that they have some properties similar to compounds. Other examples of compound-like mixtures include intermetallic compounds and solutions of metals in a liquid form of ammonia. Compounds may be described using formulas in various formats, for compounds that exist as molecules, the formula for the molecular unit is shown. For polymeric materials, such as minerals and many metal oxides, the elements in a chemical formula are normally listed in a specific order, called the Hill system

18.
Cis-trans isomerism
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Cis–trans isomerism, also known as geometric isomerism or configurational isomerism, is a term used in organic chemistry. The terms “cis” and “trans” are from Latin, Cis means that functional groups are on the same side of the carbon chain, and trans means that functional groups are on the opposite side of the carbon chain. It is not to be confused with E–Z isomerism, which is an absolute stereochemical description, in general, stereoisomers contain double bonds that cannot rotate, or they may contain ring structures, where the rotation of bonds is restricted or prevented. Cis and trans isomers occur both in organic molecules and in coordination complexes. The term geometric isomerism is considered a synonym of cis–trans isomerism by IUPAC. An example of a small hydrocarbon displaying cis–trans isomerism is but-2-ene, alicyclic compounds can also display cis–trans isomerism. As an example of a geometric isomer due to a structure, consider 1, 2-dichlorocyclohexane, Cis. Differences between isomers, in general, arise from the differences in the shape of the molecule or the dipole moment. These differences can be small, as in the case of the boiling point of straight-chain alkenes, such as pent-2-ene. The differences between cis and trans isomers can be larger if polar bonds are present, as in the 1, the cis isomer in this case has a boiling point of 60.3 °C, while the trans isomer has a boiling point of 47.5 °C. In the trans isomer on the hand, this does not occur because the two C−Cl bond moments cancel and the molecule has a net zero dipole. The two isomers of butenedioic acid have such large differences in properties and reactivities that they were given completely different names. The cis isomer is called maleic acid and the trans isomer fumaric acid, polarity is key in determining relative boiling point as it causes increased intermolecular forces, thereby raising the boiling point. In the same manner, symmetry is key in determining relative melting point as it allows for better packing in the solid state, one example of this is the relationship between oleic acid and elaidic acid, oleic acid, the cis isomer, has a melting point of 13. In the case of geometric isomers that are a consequence of double bonds, and, in particular and these trends can be attributed to the fact that the dipoles of the substituents in a cis isomer will add up to give an overall molecular dipole. In a trans isomer, the dipoles of the substituents will cancel out due to being on opposite sides of the molecule, Trans isomers also tend to have lower densities than their cis counterparts. As a general trend, trans alkenes tend to have melting points and lower solubility in inert solvents, as trans alkenes. Vicinal coupling constants, measured by NMR spectroscopy, are larger for trans than for cis isomers, usually for acyclic systems trans isomers are more stable than cis isomers

19.
Dicarboxylic acid
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A dicarboxylic acid is an organic compound containing two carboxyl functional groups. The general molecular formula for dicarboxylic acids can be written as HO2C−R−CO2H, in general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids. Dicarboxylic acids are used in the preparation of copolymers such as polyamides. The most widely used dicarboxylic acid in the industry is adipic acid, other examples of dicarboxylic acids include aspartic acid and glutamic acid, two amino acids in the human body. The PubChem links gives access to a wealth of information on the compounds, adipic acid, despite its name, is not a normal constituent of natural lipids but is a product of oxidative rancidity. It was first obtained by oxidation of castor oil with nitric acid and it is now produced industrially by oxidation of cyclohexanol or cyclohexane, mainly for the production of Nylon 6-6. Pimelic acid was also first isolated from oxidized oil, derivatives of pimelic acid are involved in the biosynthesis of lysine. Suberic acid was first produced by nitric acid oxidation of cork and this acid is also produced when castor oil is oxidised. Suberic acid is used in the manufacture of alkyd resins and in the synthesis of polyamides, azelaic acids name stems from the action of nitric acid oxidation of oleic acid or elaidic acid. It was detected among products of rancid fats and its origin explains for its presence in poorly preserved samples of linseed oil and in specimens of ointment removed from Egyptian tombs 5000 years old. Azelaic acid was prepared by oxidation of oleic acid with potassium permanganate, azelaic acid is used, as simple esters or branched-chain esters) in the manufacture of plasticizers, lubricants and greases. Azelaic acid is now used in cosmetics and it displays bacteriostatic and bactericidal properties against a variety of aerobic and anaerobic micro-organisms present on acne-bearing skin. Azelaic acid was identified as a molecule that accumulated at elevated levels in parts of plants and was shown to be able to enhance the resistance of plants to infections. Thenard isolated this compound from distillation products of beef tallow in 1802 and it is produced industrially by alkali fission of castor oil. Sebacic acid and its derivatives have a variety of uses as plasticizers, lubricants, diffusion pump oils, cosmetics, candles. It is also used in the synthesis of polyamide, as nylon, brassylic acid can be produced from erucic acid by ozonolysis but also by microorganisms from tridecane. This diacid is produced on a commercial scale in Japan for the manufacture of fragrances. Dodecanedioic acid is used in the production of nylon, polyamides, coatings, adhesives, greases, polyesters, dyestuffs, detergents, flame retardants and it is now produced by fermentation of long-chain alkanes with a specific strain of Candida tropicalis

20.
Fruit
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In botany, a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds, accordingly, fruits account for a substantial fraction of the worlds agricultural output, and some have acquired extensive cultural and symbolic meanings. On the other hand, in usage, fruit includes many structures that are not commonly called fruits, such as bean pods, corn kernels, tomatoes. The section of a fungus that produces spores is called a fruiting body. Many common terms for seeds and fruit do not correspond to the botanical classifications, however, in botany, a fruit is the ripened ovary or carpel that contains seeds, a nut is a type of fruit and not a seed, and a seed is a ripened ovule. Examples of culinary vegetables and nuts that are botanically fruit include corn, cucurbits, eggplant, legumes, sweet pepper, in addition, some spices, such as allspice and chili pepper, are fruits, botanically speaking. g. Botanically, a grain, such as corn, rice, or wheat, is also a kind of fruit. However, the wall is very thin and is fused to the seed coat. The outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, the pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp. Fruit that bears a prominent pointed terminal projection is said to be beaked, a fruit results from maturation of one or more flowers, and the gynoecium of the flower forms all or part of the fruit. Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the egg cell, after double fertilization, these ovules will become seeds. The ovules are fertilized in a process starts with pollination. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule, later the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo. As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, in some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules. The pericarp is often differentiated into two or three distinct layers called the exocarp, mesocarp, and endocarp, in some fruits, especially simple fruits derived from an inferior ovary, other parts of the flower, fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the fall off. When such other floral parts are a significant part of the fruit, it is called an accessory fruit, since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms. There are three modes of fruit development, Apocarpous fruits develop from a single flower having one or more separate carpels

21.
Taste
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Taste, gustatory perception, or gustation is one of the five traditional senses that belongs to the gustatory system. Taste is the sensation produced when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, Taste, along with smell and trigeminal nerve stimulation, determines flavors of food or other substances. Humans have taste receptors on taste buds and other areas including the surface of the tongue. The tongue is covered with thousands of small bumps called papillae, within each papilla are hundreds of taste buds. The exception to this is the filiform papillae that do not contain taste buds, there are between 2000 and 5000 taste buds that are located on the back and front of the tongue. Others are located on the roof, sides and back of the mouth, each taste bud contains 50 to 100 taste receptor cells. The sensation of taste includes five established basic tastes, sweetness, sourness, saltiness, bitterness, scientific experiments have proven that these five tastes exist and are distinct from one another. Taste buds are able to differentiate among different tastes through detecting interaction with different molecules or ions, Sweet, umami, and bitter tastes are triggered by the binding of molecules to G protein-coupled receptors on the cell membranes of taste buds. Saltiness and sourness are perceived when alkali metal or hydrogen ions enter taste buds, temperature, detected by thermoreceptors, and coolness and hotness, through chemesthesis. As taste senses both harmful and beneficial things, all basic tastes are classified as either aversive or appetitive, Sweetness helps to identify energy-rich foods, while bitterness serves as a warning sign of poisons. Among humans, taste perception begins to fade around 50 years of age because of loss of tongue papillae, Taste in the gustatory system allows humans to distinguish between safe and harmful food, and to gauge foods’ nutritional value. Digestive enzymes in saliva begin to dissolve food into base chemicals that are washed over the papillae, the tongue is covered with thousands of small bumps called papillae, which are visible to the naked eye. Within each papilla are hundreds of taste buds, the exception to this are the filiform papillae that do not contain taste buds. There are between 2000 and 5000 taste buds that are located on the back and front of the tongue, others are located on the roof, sides and back of the mouth, and in the throat. Each taste bud contains 50 to 100 taste receptor cells, bitter foods are generally found unpleasant, while sour, salty, sweet, and meaty tasting foods generally provide a pleasurable sensation. The five specific tastes received by taste receptors are saltiness, sweetness, bitterness, sourness, and umami, as of the early twentieth century, physiologists and psychologists believed there were four basic tastes, sweetness, sourness, saltiness, and bitterness. At that time umami was not identified but now a number of authorities recognize it as the fifth taste. One study found that salt and sour taste mechanisms detect, in different ways, the presence of sodium chloride in the mouth, however

22.
Salt (chemistry)
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In chemistry, a salt is an ionic compound that results from the neutralization reaction of an acid and a base. Salts are composed of related numbers of cations and anions so that the product is electrically neutral and these component ions can be inorganic, such as chloride, or organic, such as acetate, and can be monatomic, such as fluoride, or polyatomic, such as sulfate. There are several varieties of salts, salts that hydrolyze to produce hydroxide ions when dissolved in water are alkali salts, whilst those that hydrolyze to produce hydronium ions in water are acidic salts. Neutral salts are those salts that are neither acidic nor basic, zwitterions contain an anionic centre and a cationic centre in the same molecule, but are not considered to be salts. Examples of zwitterions include amino acids, many metabolites, peptides, usually, non-dissolved salts at standard conditions for temperature and pressure are solid, but there are exceptions. Molten salts and solutions containing dissolved salts are called electrolytes, as they are able to conduct electricity. As observed in the cytoplasm of cells, in blood, urine, plant saps and mineral waters, therefore, their salt content is given for the respective ions. Salts can appear to be clear and transparent, opaque, and even metallic, in many cases, the apparent opacity or transparency are only related to the difference in size of the individual monocrystals. Since light reflects from the boundaries, larger crystals tend to be transparent. The color of the salt is due to the electronic structure in the d-orbitals of transition elements or in the conjugated organic dye framework. Different salts can elicit all five basic tastes, e. g. salty, sweet, sour, bitter, and umami or savory. Salts of strong acids and strong bases are non-volatile and odorless and that slow, partial decomposition is usually accelerated by the presence of water, since hydrolysis is the other half of the reversible reaction equation of formation of weak salts. Many ionic compounds can be dissolved in water or other similar solvents, the exact combination of ions involved makes each compound have a unique solubility in any solvent. The solubility is dependent on how well each ion interacts with the solvent, for example, all salts of sodium, potassium and ammonium are soluble in water, as are all nitrates and many sulfates – barium sulfate, calcium sulfate and lead sulfate are examples of exceptions. However, ions that bind tightly to each other and form highly stable lattices are less soluble, for example, most carbonate salts are not soluble in water, such as lead carbonate and barium carbonate. Some soluble carbonate salts are, sodium carbonate, potassium carbonate, solid salts do not conduct electricity. Moreover, solutions of salts also conduct electricity, the name of a salt starts with the name of the cation followed by the name of the anion. Salts are often referred to only by the name of the cation or by the name of the anion. g

23.
Ester
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In chemistry, esters are chemical compounds derived from an acid in which at least one –OH group is replaced by an –O–alkyl group. Usually, esters are derived from an acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the classes of lipids. Esters with low weight are commonly used as fragrances and found in essential oils. Phosphoesters form the backbone of DNA molecules, nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties. The word ester was coined in 1848 by German chemist Leopold Gmelin, probably as a contraction of the German Essigäther, ester names are derived from the parent alcohol and the parent acid, where the latter may be organic or inorganic. Esters derived from more complex carboxylic acids are, on the hand, more frequently named using the systematic IUPAC name. For example, the ester hexyl octanoate, also known under the trivial name hexyl caprylate, has the formula CH36CO25CH3, the chemical formulas of organic esters usually take the form RCO2R′, where R and R′ are the hydrocarbon parts of the carboxylic acid and the alcohol, respectively. For example, butyl acetate, derived from butanol and acetic acid would be written CH3CO2C4H9, alternative presentations are common including BuOAc and CH3COOC4H9. Cyclic esters are called lactones, regardless of whether they are derived from an organic or an inorganic acid, one example of a lactone is γ-valerolactone. An uncommon class of organic esters are the orthoesters, which have the formula RC3, triethylorthoformate is derived, in terms of its name from orthoformic acid and ethanol. Esters can also be derived from an acid and an alcohol. For example, triphenyl phosphate is the derived from phosphoric acid. Organic carbonates are derived from acid, for example, ethylene carbonate is derived from carbonic acid. So far an alcohol and inorganic acid are linked via oxygen atoms, in corollary, boron features borinic esters, boronic esters, and borates. As oxygen is a group 16 chemical element, sulfur atoms can replace some oxygen atoms in carbon–oxygen–central inorganic atom covalent bonds of an ester, esters contain a carbonyl center, which gives rise to 120 ° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier and their flexibility and low polarity is manifested in their physical properties, they tend to be less rigid and more volatile than the corresponding amides. The pKa of the alpha-hydrogens on esters is around 25, the preference for the Z conformation is influenced by the nature of the substituents and solvent, if present

24.
Furfural
–
Furfural /ˈfɜːrfjᵿræl/ is an organic compound derived from a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word furfur, meaning bran, Furfural is a heterocyclic aldehyde, with the ring structure shown at right. It is an oily liquid with the odor of almonds. It is one of the found in vanilla. Furfural was first isolated in 1821 by the German chemist Johann Wolfgang Döbereiner, at the time, formic acid was formed by the distillation of dead ants, and Döbereiners ant bodies probably contained some plant matter. George Fownes named this oil furfurol in 1845 and this name persisted prominently in the literature until 1901 when the German chemist Carl Harries deduced furfurals structure. Except for occasional use in perfume, furfural remained a relatively obscure chemical until 1922, today, furfural is still produced from agricultural byproducts like sugarcane bagasse and corn cobs. The main countries producing furfural today are the Dominican Republic, South Africa, furfurals physical properties are summarized in the table at top right. Furfural dissolves readily in most polar solvents, but is only slightly soluble in either water or alkanes. Chemically, furfural participates in the kinds of reactions as other aldehydes. Indicating its diminished aromaticity relative to benzene, furfural is readily hydrogenated to the corresponding tetrahydrofuran derivatives, when heated in the presence of acids, furfural irreversibly solidifies, i. e. a thermosetting polymer. Furfural may be obtained by the acid catalyzed dehydration of 5-carbon sugars and these sugars may be obtained from hemicellulose present in lignocellulosic biomass and as such furfural may be considered a green chemical. Furfural and water evaporate together from the mixture, and separate upon condensation. The global production capacity is about 800,000 tons as of 2012, China is the biggest supplier of furfural, and accounts for the greater part of global capacity. The other two major producers are Illovo Sugar in the Republic of South Africa and Central Romana in the Dominican Republic. In the laboratory, synthesis of furfural from corn cobs takes place by reflux with dilute sulfuric acid, the lignocellulosic residue that remains after the removal of the furfural is used to generate all the steam requirements of the furfural plant. Newer and more efficient plants have excess residue, which is or can be used for co-generation of electricity, cattle feed, activated carbon, mulch/fertiliser. It also has used as a glue extender in the North American board industry

25.
Vanadium
–
Vanadium is a chemical element with symbol V and atomic number 23. It is a hard, silvery grey, ductile, and malleable transition metal, the elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer stabilizes the free metal somewhat against further oxidation. Four years later, however, he was convinced by other scientists that erythronium was identical to chromium, both names were attributed to the wide range of colors found in vanadium compounds. Del Rios lead mineral was later renamed vanadinite for its vanadium content, in 1867 Henry Enfield Roscoe obtained the pure element. Vanadium occurs naturally in about 65 different minerals and in fossil fuel deposits and it is produced in China and Russia from steel smelter slag, other countries produce it either from the flue dust of heavy oil, or as a byproduct of uranium mining. It is mainly used to produce specialty steel alloys such as high-speed tool steels, the most important industrial vanadium compound, vanadium pentoxide, is used as a catalyst for the production of sulfuric acid. Large amounts of ions are found in a few organisms. The oxide and some salts of vanadium have moderate toxicity. Particularly in the ocean, vanadium is used by life forms as an active center of enzymes. Vanadium was discovered by Andrés Manuel del Río, a Spanish-Mexican mineralogist, Del Río extracted the element from a sample of Mexican brown lead ore, later named vanadinite. He found that its salts exhibit a variety of colors. Later, Del Río renamed the element erythronium because most of the salts turned red upon heating, Del Río accepted Collet-Descotils statement and retracted his claim. In 1831, the Swedish chemist Nils Gabriel Sefström rediscovered the element in a new oxide he found working with iron ores. Later that same year, Friedrich Wöhler confirmed del Ríos earlier work, Sefström chose a name beginning with V, which had not been assigned to any element yet. He called the element vanadium after Old Norse Vanadís, because of the many beautifully colored chemical compounds it produces, in 1831, the geologist George William Featherstonhaugh suggested that vanadium should be renamed rionium after del Río, but this suggestion was not followed. The isolation of vanadium metal proved difficult, in 1831, Berzelius reported the production of the metal, but Henry Enfield Roscoe showed that Berzelius had in fact produced the nitride, vanadium nitride. Roscoe eventually produced the metal in 1867 by reduction of chloride, VCl2. In 1927, pure vanadium was produced by reducing vanadium pentoxide with calcium, the first large-scale industrial use of vanadium was in the steel alloy chassis of the Ford Model T, inspired by French race cars

26.
Catalyst
–
Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, furthermore, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often only tiny amounts are required in principle, in the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations, the effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons or promoters. Catalyzed reactions have an activation energy than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature. However, the mechanics of catalysis is complex. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst, in heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. A nanomaterial-based catalyst is an example of a heterogeneous catalyst, analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts. Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, in heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a system or sublimate in a solid–gas system. The production of most industrially important chemicals involves catalysis, similarly, most biochemically significant processes are catalysed. Research into catalysis is a field in applied science and involves many areas of chemistry, notably organometallic chemistry. Catalysis is relevant to aspects of environmental science, e. g. the catalytic converter in automobiles. Many transition metals and transition metal complexes are used in catalysis as well, Catalysts called enzymes are important in biology. A catalyst works by providing a reaction pathway to the reaction product. The rate of the reaction is increased as this route has a lower activation energy than the reaction route not mediated by the catalyst. The disproportionation of hydrogen peroxide creates water and oxygen, as shown below,2 H2O2 →2 H2O + O2 This reaction is preferable in the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available and this reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms

27.
Isomerisation
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In chemistry isomerization is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms have a different arrangement e. g. A-B-C → B-A-C. In some molecules and under conditions, isomerization occurs spontaneously. When the isomerization occurs intramolecularly it is considered a rearrangement reaction, an example of an organometallic isomerization is the production of decaphenylferrocene, from its linkage isomer. Isomerization in hydrocarbon cracking is usually employed in chemistry, where fuels, such as diesel or pentane. The straight- and branched-chain isomers in the mixture then have to be separated. Another industrial process is the isomerisation of n-butane into isobutane, trans-cis isomerism is where, in certain compounds, an interconversion of cis and trans isomers can be observed. For instance, with acid and with azobenzene, often by photoisomerization. g. Bullvalene, and valence isomerization, the isomerization of molecules which involve structural changes resulting only from a relocation of single and double bonds, if a dynamic equilibrium is established between the two isomers it is also referred to as valence tautomerism. In a cycloisomerization a cyclic compound is formed, isomerization reactions can also be found with specific aromatic hydrocarbons. The energy difference between two isomers is called isomerization energy

28.
Functional group
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In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of, however, its relative reactivity can be modified by other functional groups nearby. The atoms of functional groups are linked to other and to the rest of the molecule by covalent bonds. Any subgroup of atoms of a compound also may be called a radical, and if a covalent bond is broken homolytically, Functional groups can also be charged, e. g. in carboxylate salts, which turns the molecule into a polyatomic ion or a complex ion. Complexation and solvation is also caused by interactions of functional groups. In the common rule of thumb like dissolves like, it is the shared or mutually well-interacting functional groups give rise to solubility. For example, sugar dissolves in water because both share the functional group and hydroxyls interact strongly with each other. Combining the names of groups with the names of the parent alkanes generates what is termed a systematic nomenclature for naming organic compounds. In traditional nomenclature, the first carbon atom after the carbon that attaches to the group is called the alpha carbon, the second, beta carbon. IUPAC conventions call for numeric labeling of the position, e. g. 4-aminobutanoic acid, in traditional names various qualifiers are used to label isomers, for example isopropanol is an isomer is n-propanol. The following is a list of functional groups. In the formulas, the symbols R and R usually denote an attached hydrogen, or a side chain of any length. Functional groups, called hydrocarbyl, that only carbon and hydrogen. Each one differs in type of reactivity, there are also a large number of branched or ring alkanes that have specific names, e. g. tert-butyl, bornyl, cyclohexyl, etc. Hydrocarbons may form charged structures, positively charged carbocations or negative carbanions, examples are tropylium and triphenylmethyl cations and the cyclopentadienyl anion. Haloalkanes are a class of molecule that is defined by a carbon–halogen bond and this bond can be relatively weak or quite stable. In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions, the substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity. Compounds that contain nitrogen in this category may contain C-O bonds, compounds that contain sulfur exhibit unique chemistry due to their ability to form more bonds than oxygen, their lighter analogue on the periodic table

ChemSpider
–
ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The

1.
ChemSpider

DrugBank
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The DrugBank database is a comprehensive, freely accessible, online database containing information on drugs and drug targets. As both a bioinformatics and a resource, DrugBank combines detailed drug data with comprehensive drug target information. Because of its scope, comprehensive referencing and unusually detailed data descriptions. As a result

1.
Fig. 1. DrugBank DrugCard

E number
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E numbers are codes for substances that are permitted to be used as food additives for use within the European Union and Switzerland. Commonly found on labels, their safety assessment and approval are the responsibility of the European Food Safety Authority. Having a single unified list for food additives was first agreed upon in 1962 with food col

1.
A solution of E101 riboflavin (also known as vitamin B2)

2.
Crystals of E621 Monosodium glutamate, a flavour enhancer

International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL lic

1.
L - ascorbic acid

Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specifi

1.
Generation of SMILES: Break cycles, then write as branches off a main backbone. (Ciprofloxacin)

Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of

1.
Al 2 (SO 4) 3

Density
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The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume, ρ = m V, where ρ is the density, m is the mass, and V is the volume. In some cases, density

1.
Air density vs. temperature

Melting point
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The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid

Aqueous solution
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An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant chemical formula, for example, a solution of table salt, or sodium chloride, in water would be represented as Na+ + Cl−. The word aqueous means pertaining to, related to, similar to, as water is an excellent solven

1.
The first solvation shell of a sodium ion dissolved in water.

Acid dissociation constant
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An acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the constant for a chemical reaction known as dissociation in the context of acid–base reactions. In the example shown in the figure, HA represents acetic acid, and A− represents the acetate ion, the chemical species HA, A− and H3O+ are said t

Carboxylic acid
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A carboxylic acid /ˌkɑːrbɒkˈsɪlɪk/ is an organic compound that contains a carboxyl group. The general formula of an acid is R–COOH, with R referring to the rest of the molecule. Carboxylic acids occur widely and include the amino acids and acetic acid, salts and esters of carboxylic acids are called carboxylates. When a carboxyl group is deprotonat

1.
Structure of a carboxylic acid

Maleic acid
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Maleic acid or cis-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Maleic acid is the cis-isomer of butenedioic acid, whereas fumaric acid is the trans-isomer and it is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications.

2.
Maleic acid

Succinic acid
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Succinic acid is a dicarboxylic acid with the chemical formula 22. The name derives from Latin succinum, meaning amber, succinate is generated in mitochondria via the tricarboxylic acid cycle, an ancient energy-yielding process shared by all organisms. As such, succinate links cellular metabolism to the regulation of cellular function, dysregulatio

2.
Succinic acid

Crotonic acid
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Crotonic acid or is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. It is also called crotonic acid because it was thought to be a saponification product of croton oil. It crystallizes as needles from hot water, the cis-isomer of crotonic acid is called isocrotonic acid. 0°. The unit cell contains four formula unit

1.
Crotonic acid

Dimethyl fumarate
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Dimethyl fumarate is the methyl ester of fumaric acid. DMF was initially recognized as a very effective hypoxic cell radiosensitizer, later, DMF combined with three other fumaric acid esters was licensed in Germany as oral therapy for psoriasis. Other diseases, such as necrobiosis lipoidica, granuloma annulare, phase III clinical trials found that

1.
Dimethyl fumarate

Iron(II) fumarate
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Iron fumarate, also known as ferrous fumarate, is the iron salt of fumaric acid, occurring as a reddish-orange powder, used to supplement iron intake. It has the chemical formula C4H2FeO4, pure ferrous fumarate has an iron content of 32. 87%, therefore one tablet of 300 mg iron fumarate will contain 98.6 mg of iron. Ferrous fumurate is often taken

1.
Iron(II) fumarate

Chemical compound
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A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can

1.
Pure water (H 2 O) is an example of a compound: the ball-and-stick model of the molecule (above) shows the spatial association of two parts hydrogen (white) and one part oxygen (red)

Cis-trans isomerism
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Cis–trans isomerism, also known as geometric isomerism or configurational isomerism, is a term used in organic chemistry. The terms “cis” and “trans” are from Latin, Cis means that functional groups are on the same side of the carbon chain, and trans means that functional groups are on the opposite side of the carbon chain. It is not to be confused

1.
cis -but-2-ene

Dicarboxylic acid
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A dicarboxylic acid is an organic compound containing two carboxyl functional groups. The general molecular formula for dicarboxylic acids can be written as HO2C−R−CO2H, in general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids. Dicarboxylic acids are used in the preparation of copolymers such as polyamide

Fruit
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In botany, a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds, accordingly, fruits account for a substantial fraction of the worlds agricultural output, and some have acquired extensive cultural and symbolic meanings. On the other hand, in usag

1.
Culinary fruits

2.
Several culinary fruits

3.
Mixed fruit

4.
Fruit shop in Naggar, Himachal Pradesh, India

Taste
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Taste, gustatory perception, or gustation is one of the five traditional senses that belongs to the gustatory system. Taste is the sensation produced when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, Taste, along with smell and trigeminal nerve stimulation, determines flavors of food

1.
Taste bud

Salt (chemistry)
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In chemistry, a salt is an ionic compound that results from the neutralization reaction of an acid and a base. Salts are composed of related numbers of cations and anions so that the product is electrically neutral and these component ions can be inorganic, such as chloride, or organic, such as acetate, and can be monatomic, such as fluoride, or po

1.
The salt copper(II) sulfate as the mineral chalcanthite.

2.
Potassium dichromate, a bright orange salt used as a pigment.

3.
Solid lead(II) sulfate (PbSO 4)

Ester
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In chemistry, esters are chemical compounds derived from an acid in which at least one –OH group is replaced by an –O–alkyl group. Usually, esters are derived from an acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the classes of lipids. Esters with low weight are commonly used

1.
A carboxylate ester. R and R' denote any alkyl or aryl group. R can also be a hydrogen atom

Furfural
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Furfural /ˈfɜːrfjᵿræl/ is an organic compound derived from a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word furfur, meaning bran, Furfural is a heterocyclic aldehyde, with the ring structure shown at right. It is an oily liquid with the odor of almonds. It is one of

Vanadium
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Vanadium is a chemical element with symbol V and atomic number 23. It is a hard, silvery grey, ductile, and malleable transition metal, the elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer stabilizes the free metal somewhat against further oxidation. Four years later, however, he was convinc

Catalyst
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Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, furthermore, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often onl

1.
An air filter that utilizes low-temperature oxidation catalyst used to convert carbon monoxide to less toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air.

2.
Zeolites are extruded as pellets for easy handling in catalytic reactors.

Isomerisation
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In chemistry isomerization is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms have a different arrangement e. g. A-B-C → B-A-C. In some molecules and under conditions, isomerization occurs spontaneously. When the isomerization occurs intramolecularly it is considered a rearrange

1.
Instances of isomerization [edit]

Functional group
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In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of, however, its relative reactivity can be

1.
Benzyl acetate has an ester functional group (in red), an acetyl moiety (circled with dark green) and a benzyloxy moiety (circled with light orange). Other divisions can be made.

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The world’s first ice-calorimeter, used in the winter of 1782-83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat evolved in various chemical changes; calculations which were based on Joseph Black ’s prior discovery of latent heat. These experiments mark the foundation of thermochemistry.

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A fluorescent image of an endothelial cell. Nuclei are stained blue, mitochondria are stained red, and microfilaments are stained green.

4.
Human cancer cells with nuclei (specifically the DNA) stained blue. The central and rightmost cell are in interphase, so the entire nuclei are labeled. The cell on the left is going through mitosis and its DNA has condensed.

2.
Sodium and fluorine bonding ionically to form sodium fluoride. Sodium loses its outer electron to give it a stable electron configuration, and this electron enters the fluorine atom exothermically. The oppositely charged ions are then attracted to each other. The sodium is oxidized, and the fluorine is reduced.

1.
The electron transport chain in the mitochondrion is the site of oxidative phosphorylation in eukaryotes. The NADH and succinate generated in the citric acid cycle are oxidized, providing energy to power ATP synthase.